Flameproof fibrous aminoethylated cellulose derivatives



Patented Feb. 2 1954 FLAMEPRO-OF FIBROUS AMINOETHYLATED CELLULOSEDERIVATIVES Wilson A. Reeves and John D. Guthrie, New rleans, La.,assignors to the United States of America as represented by theSecretary of Agriculture No Drawing. Application April 22, 1952,

, Serial No. 283,743

(Granted under Title 35, U. S. Code (1952),

sec. 266) 6 Claims.

A non-exclusive, irrevocable, royalty-free license in the inventionherein described, for all governmental purposes, throughout the world,

. with the power to grant sublicenses for such purposes, is herebygranted to the Government of the United States of America. 7

This invention relates to fibrous cellulose derivatives containingphosphorus and nitrogen atoms and to a process for their production;

Cellulose fibers in the form of free fibers, textiles, or textileintermediates such as slivers, yarns, threads, and the like, can beconverted to fibrous cellulose derivatives containing primary aminogroups. For example, U. S. 2,459,222 describes and claims such a processby which cellulose is wetted with an aqueous solution of sodiumhydroxide containing 2-amino ethyl sulfuric acid. The treated celluloseis heated at a temperature of from about '70 to 110 C. for a minimumperiod of from 40 minutes to 9 hours, after which the cellulose iswashed to remove sodium hydroxide. Nitrogen up to about 0.6% is readilyintroduced by this procedure.

We have discovered that fibrous cellulose derivatives containing primaryamino groups react with tetrakis(hydroxymethyl) phosphonium chloride toproduce fibrous cellulose derivatives containing phosphorus as well asnitrogen. The combustibility of these phosphorus and nitrogencontainingcellulose derivatives is markedly lower than that of cellulose fibers oraminized cellulose fibers and the groups responsible for the loweredcombustibility appear to be attached to the cellulose fibers byrelatively strong chemical bonds.

We have also discovered that the reaction of tetrakis(hydroxymethyl)phosphonium chloride with the primary amino groups of aminized celluloseoccurs concurrently with reactions of tetrakis(hydroxymethyl)phosphonium chloride with at least one polyamido compound of the groupconsisting of melamine, guanidine and urea as well as with reactions oftetrakis(hy droxymethyl) phosphonium chloride with such polyamidocompounds and with formaldehyde when the polyamido compound or when boththe polyamido compound and the formaldehyde are 1 in contact with theaminized cellulose during its reaction with tetrakis(hydroxymethyl) tilematerials.

In general, according to this invention, aminized cellulose fiberscontaining primary amino groups: are converted to fibrous derivatives ofcellulose containing phosphorus and nitrogen atoms by reacting them withtetrakis- (hydroxymethyl) phosphonium chloride; are converted to fibrousderivatives of cellulose containing phosphorus and nitrogen atoms andimpregnated with a chemically bonded condensation polymer of tetrakishydroxymethyl phosphonium chloride and at least one polyamido compoundof the group consisting of melamine, guanidine and urea by reacting themwith tetrakis hydroxymethyl phosphonium chloride and the polyamidocompound; and are converted to fibrous derivatives of cellulosecontaining phosphorus and nitrogen atoms and impregnated with achemically bonded condensation polymer of tetrakis(hydroxymethyl)phosphonium chloride and such a polyamido compound for formaldehyde byreacting them with tetrakis(hydroxymethyl) phosphonium chloride and thepolyamido compound and formaldehyde.

. textiles, or textile intermediates, to fibers havwith ing specialproperties and having a hand and feel comparable to those of aminizedcellulose fibers, but having a lower combustibility than eitherunmodified cellulose fibers or aminized cellulose fibers.

The fibrous derivatives of cellulose provided by this invention arerelatively durable and laundering and the like treatments makecomparatively small changes in their resistance to burning. Thederivatives are particularly suitable for use in the production offabrics for military and the like uses where low combustibility isdesired.

Preferred aminized cellulose fibers for conversion. by the presentprocess consist of spun weight.

The reaction of the aminized cellulose fibers tetrakis hydroxymethybphosphonium chloride alone is perferably conducted by: impregnating thecellulose fibers with an aqueous j solution containing from about 5 toabout 35% of tetrakis(hydroxymethyl) phosphonium chloride; mechanicallyremoving the excess liquid and curing the impregnated fabrics at fromabout to about 160 C. for from about 4 to about 30 minutes, using thelonger times with the lower temperatures. The uncombined reagents arepreferably removed from the cured fibers by water washing. Sheconcentration of tetrakis- (hydroxymethyl) phosphonium chloride in theaqueous impregnating liquidzandithecurmg times and temperatures cansuitably be variediwidely.

The reaction of the aminizedcellulose fibers concurrently withtetrakislhydroxymethyll phosphonium chloride and with .a polyamidocompound is preferably conducted by: dissolving the polyamido compoundand from about 1 to about 2 parts of tetrakis(hydroxymethyl) phosphom'umchloride per part of unsubstituted amido group presented by thepolyamido .compound in from about 3 to about parts of water per part oftotal Weight of polyamido'compound and phosphonium chloride by agitatinga mix ture of the polyamido compound, the phosphonium chlorideand'waterat from-abQut' ZE to about-80 0.; impregnating the cellulosefibers "with the resultant aqueous solution and curing the impregnatedfabrics at from about 80 toabout 160 :C. for from about i "to about :30minutes,

using the longer times'with the lower tempera- 'tures.

The reaction of the aminized cellulose lfibers 'concurrently'withtetrakisChydroxymethyl) zphosphonium chloride:and polyamide compound andformaldehyde is preferably conducted by: unixaldehyde, dissolving theresul-tant mixture Lin a weight of water about equal to :the weight ofthe mixture and warming 1 the solution until it has a viscosity slightlygreater than *that of water, impregnating the cellulose lfiber 'with the'solution'so produce'dyandcuring the impregnated fibers at from about80to=aboutl60 1C. for from about A to "about 30 minutes, using i'thelonger times with the lower temperatures.

A water-soluble, basically reacting compound can suit-ably be used toneutralize any hydrochlori'c acid formed during reaction of tetrakis-*(hydroxymethyl) phosphonium chloridewith-an amino 'or 'amido group.Such a neutralization reduces the tendency-o'f-the acid to decre'ase thetensile strength of fibrous cellulose=derivatives Neutralization ispreferably l accomplished by the use "of a water-soluble'carbonate suchas sodium carbonate or guanidine carbonate, 'or by-"adding urea to thereaction'mixture. The-'presenceofa i a slight excess'o'f awater-soluble'base"-isadvantageous in thatit catalyzes someofthedescribed reactions. The presence of urea is advantageous in' that*ureaappears to react I and' -beeome chemically combined with thefibrous 'cellulose'derivatives, increasingtheirnitrogen content and'thusgenerally increasing their resistanceto burning.

The following examples are illustrative 0'1" the invention:

'Example 1 A 33% aqueous solution of tetrakis(hydnoxymethyl)iphosphonium chloride was swabbed onto :a :highly aminized cotton clothtprepared .in

accordance with the process .of us. 2,459,222 andhaving a nitrogencontent .of 1.6 9211. The

impregnated cloth was cured-at .11.? .to 120 .for minutes, washedior 1.hours with'hot tap 'water, and dried.

Although the treated cloth was -stifi and.

boardy than was the cloth prior to reaction with tetrakismydroxymethyl).phosphonium chloride. 'The treatedploth would do the'il3'0' to angleflame test with no afterglow. The treated cloth .retained its flameandglow-resistance after 1 hour in a boiling solution of 5 g. of A. S. T.M. istandardsoapflakes (D496-39) and 1 g. of sodium :carbonate in 500mm. of water. It also retained .its flameand glow-resistance after'beingfb'd-iled ior hours and 45 minutes in an -aqueous 1%..sodiumhydroxide solution.

Example 2 A piece 'of aminizerl fabric (prepared in acrordance with theprocess of U. S. 2,459,222, having an N content of 0.67%) wasimpregnated with a solution prepared by mixing a mixture ofte'trakisfihydroxymethyl) phosphonium chloride and melamine in about a2:1 weight ratio with an approximately equal weight of water c'ontaininga small zainount .of "acetic "acid, and agitating :the mixture for about20 minutes at .rabout :80 to 190 C. .The impregnated :fabricwas"dried1at180iC.2ancl:cured 5 minutes'at *"0.

The treated .cloth would do the $180 angle flame test after it waswashed. iorllli hours with ihotiap water. Afterzitwas' boilediforfiominutes in $24.11 "aqueous -1% sodium hydroxide isolutionrit would 1:10the ;180angle flame test with: aisl'rght :burning.

A ,piece of aminized fabric (prepared in accordance with'the process or'U."S.2;4'59,222'.having a nitrogen content o'f'0.6'7'%) was'impregnatedwitha solution prepared bymiiiingtwoparts .of tetrakismydroxymethyl)phosphom'um chlori'de with one part of 'methylol melamine and three,partsof .water at. rooin'temperature, The impregnated fabric was -driedat "65 "C. and .cured 'minutes at C.

The resultant fabric was completely flameproof. The fabric would'notburn even aifter boiling or3'0 minutes in a "1% seem solution containing0.2% sodium carbonate.

Weclaim:

.1. AQfibrous derivative .of cellulose, containing ,phosphorusandnitrogen atoms, produced by reacting .aminized cellulose fibers,.containing a v.pluralitypf primary amino groups, with tetrakis-Khydroxymethyil) ,phosphonium chloride.

2. A .fibrous derivative of .cellulose, containing phosphorus.andnitrogen atoms and impregnated with a chemically bonded condensationpolymer of tetrakisthydroxymethyl) phosphonium chloride and .melamine,produced .by reacting .aminized cellulose fibers, containing .aplurality .of amino groups, with an aqueous solution of ,partiallyreacted .tetrakismydroxymethyl) phos- ,phonium chloride and melamine.

3. -A :fibrous derivative of cellulose containing phosphorus andnitrogen atoms andimpregnated 'with a. chemically bonded' condensationpolymer :of itetrakismydroxymethyl) gphosphonium :chloride and at least:one *polyam-ido :compound of the group-consisting ofmelamine,guanidine-iand 'urea produced by impregnating aminized :cellulose fibers-contalin'ing a plurality :of primary amino groups with an aqueoussolution -'of a partially reacted mixture or "tetrakislhydroxymethyl)phosphonium chloride and said poly- -amido "compound and curing theimpregnated fibers at from-aboutto to about C. for from about 4-to'ab'out 30 minutes, using 1 the "longer boardy, it was notappreciably 'stifie f 9; more '75 times with the lower temperatures.

4. A process of reducing the combustibility of aminized cotton fabricscomprising impregnating said fabrics with an aqueous solution oftetrakis- (hydroxymethyl) phosphonium chloride and curing theimpregnated fabrics at from about 80 to about 160 C. for from about 4 toabout 30 minutes, using the longer times with the lower temperatures.

5. A process of flameproofing a cotton fabric which comprises:aminoethylating the fabric until it contains from about 0.3 to about1.5% nitrogen; impregnating the aminoethylated fabric with a watersolution of at least one of the three members of the group consisting of(1) tetrakis hydroxymethyb phosphonium chloride, (2) water solublepartial reaction products of tetrakis(hydroxymethyl) phosphoniumchloride and a polyamide of the group consisting of melamine, guanidineand urea, and (3) water soluble partial reaction products of tetrakis-(hydroxymethyl) phosphonium chloride, formaldehyde, and a polyamide ofthe group consisting of melamine, guam'dine and urea; and curing theimpregnated fabric at from about 80 to about 6 160 C. for from about 4to about minutes, using the longer times with the lower temperatures.

6. A process comprising: impregnating an aminized cellulose fabriccontaining a plurality of primary amino groups with a water-solution ofat least one of the three members of the group consisting of (1)tetrakis(hydroxymethyl) phosphonium chloride, (2) water soluble partialreaction products of tetrakis hydroxymethyl phosphonium chloride and apolyamide of the group consisting of melamine, guanidine and urea, and(3) water soluble partial reaction products of tetrakis(hydroxymethyl)phosphonium.

chloride, formaldehyde, and a polyamide of the group consisting ofmelamine, guanidine and urea; and curing the impregnated fabric at fromabout to about C. for from about 4 to about 30 minutes, using the longertimes with the lower temperatures.

WILSON A. REEVES.

JOHN D. GUTHRIE.

No references cited.

6. A PROCESS COMPRISING: IMPREGNATING AN AMINIZED CELLULOSE FABRICCONTAINING A PLURALITY OF PRIMARY AMINO GROUPS WITH A WATER SOLUTION OFAT LEAST ONE OF THE THREE MEMBERS OF THE GROUP CONSISTING OF (1)TETRAKIS (HYDROXYMETHYL) PHOSPHONIUM CHLORIDE, (2) WATER SOLUBLE PARTIALREACTION PRODUCTS OF TETRAKIS (HYDROXYMETHYL) PHOSPHONIUM CHLORIDE AND APOLYAMIDE OF THE GROUP CONSISTING OF MELAMINE, GUANIDINE AND UREA, AND(3) WATER SOLUBLE PARTIAL REACTION PRODUCTS OF TETRAKIS (HYDROXYMETHYL)PHOSPHONIUM CHLORIDE, FORMALDEHYDE, AND A POLYAMINE OF THE GROUPCONSISTING OF MELAMINE, GUANIDINE AND UREA; AND CURING THE IMPREGNATEDFABRIC AT FROM ABOUT 80 TO ABOUT 160* C. FOR FROM ABOUT 4 TO ABOUT 30MINUTES, USING THE LONGER TIMES WITH THE LOWER TEMPERATURES.